An Approximation to a Multiple-Comparison Test

A quick graphical means of approximating a standard multiple-comparison test amounts to using upper and lower limits which are multiples of the standard error, just as in the Dice-Leraas method, but using the square root of the number of means being considered as multiplier rather than t values or 2 as multiplier. Non-overlap of limits is then considered as evidence of significantly different means. For large numbers of means, the test becomes quite conservative and it is suggested that inner limits 9/10 the size of the above will be preferable, particularly when sample sizes are nearly equal for a given pair of means.